Portable electronic devices have experienced consistently increasing popularity, with correspondingly expanded versatility and functionality including combined voice, text, email, and internet communications, gaming applications, audio and video media capability, and imaging, navigation, scheduling, and voice recognition features. To accommodate this broad range of functionality, cameras and other on-board devices are designed for precise mechanical positioning, as accomplished via a range of electromechanical devices including voice coil motor (VCM) actuators.
To provide photographic, video capture and other imaging functions, for example, a digital camera assembly or other electronic imaging system may be provided. Typically, a photodetector or other light collecting element is utilized, such as CCD (charge-coupled device) or CMOS (complementary metal oxide semiconductor) array, in combination with a lens system for focusing images onto the photosensitive surface.
For improved focal range and image quality, a voice coil actuator or other electromechanical element may be provided to position the lens with respect to the focal plane. Where active positioning is used in a portable device, however, a range of engineering challenges must be addressed, including the need for lightweight devices with a small size envelope, in combination with improved durability and resistance to vibration, shock, and other mechanical effects.